Activating of peroxygen compounds



these requirements in the United States Patent ACTIVATING OF PEROXYGEN COMPOUNDS Donald G. MacKellar, Trenton, John H. Blumbergs,

Highland Park, and Harry M. Castrantas, Trenton,

N..l., assignors to FMC Corporation, New York, N.Y.,

a corporation of Delaware No Drawing. Filed Dec. 28, 1964, Ser. No. 421,652

12 Claims. (Cl. 252-486) ABSTRACT OF THE DISCLOSURE A process for activating peroxygen compounds, including both solid and liquid peroxygen compounds, for bleaching, disinfecting and sanitizing uses comprising adding as an activator a mixed carboxylic acid anhydride having the formula:

0 0 R -('i0- ii-R where (1) R is an aliphatic group and is derived from an aliphatic monocarboxylic acid having from 2 to about 19 carbon atoms, and

(2) R is an aromatic group and This invention relates to peroxygen compositions and preferably to a method for activating peroxygen compositions which contain a solid peroxygen compound to provide bleaching and/or disinfecting and sanitizing action.

In the make-up of granular laundering compositions, it is desired to add a solid bleaching agent to the formulation in order to obtain bleaching simultaneously with cleaning. The solid bleaching agent ideally must be one which is stable at room temperature, thereby assuring good shelf life, but which is capable of bleaching at the temperatures normally employed in domestic washing machines. One class of compounds which approaches solid peroxygen compounds such as the alkali perborates. The difficulty with these solid bleaching agents is that they do not bleach effec-' tively until boiling temperatures are employed. Since the temperature of the water in domestic washing 'machines does not normally rise above about 80 C., the full bleaching effect of the peroxygen compound is not obtained.

In an effort to solve this difiiculty, many activators have been suggested in the prior art in order to permit the active oxygen compounds, e.g., perborates, to bleach effectively at lower temperatures. Many such activators have been suggested, such as esters of phenol or substituted phenols (US. Patent 3,130,165, issued April 12, 1964 to Peter Brocklehurst) and certain organic acid anhydrides (US. Patent 2,362,401, issued Nov. 7, 1944 to Joseph S. Reichert et -al.). While these activators have been found somewhat effective, the degree of activation obtained leaves much to be desired. As a result there is a need for a more effective activator than those presently employed in the art so that better bleaching can be obtained with these solid peroxygen bleaching compounds.

ingredients. These include wash water to It is an object of the present invention to incorporate an activator in compositions containing peroxygen compounds in order to enhance the bleaching, disinfecting and sanitizing powers of these compositions when used in aqueous solutions at temperatures below boiling.

These and other objects will be apparent from the following description.

We have now found that peroxygen compounds, including both solid peroxygen compounds and liquids such as hydrogen peroxide can be activated to bleach, disinfect and sanitize more eifectively when used in aqueous solutions at temperatures below boiling by incorporating as an activator, either (a) a mixed carboxylic acid anhydride having the formula:

0 R -t'i-O- -12: where (1) R is an aliphatic group and R1 (I I) is derived from an aliphatic monocarboxylic acid having from 2 to about 19 carbon atoms, and

(2) R is an aromatic group and o LL is derived from an aromatic carboxylic acid which may be a monoor polycarboxylic acid in which any additional carboxylic acid substituents are not attached to adjoining carbon atoms of the aromatic ring, or (b) a mixture of about equal molar amounts of 1) An aliphatic monocarboxylic acid anhydride derived from an aliphatic monocarboxylic acid having from 2 to about 19 carbon atoms, and

(2) An aromatic carboxylic acid anhydride derived from either an aromatic monoor polycarboxylic acid, in which any additional carboxylic acid groups are not attached to adjoining carbon atoms of the aromatic ring. The activator must be soluble in the aqueous treating solution in amounts of at least about p.p.m.

In practicing the present invention for making up detergent mixtures, the solid peroxygen compound is mixed together with a phosphate builder such as sodium tripolyphosphate in combination with one or more working antiredeposition agents such as sodium carboxymethylcellulose, anionic or nonionic surfactants and anticorrosion agents such as sodium silicate.

The activator is added to the mixture preferably in an amount sufiicient to have about one hole of anhydride present for every atom of available oxygen. Obviously, larger amounts of the activator can be used to assure complete activation of the peroxygen compound. Also, smaller amounts of the activator can be employed where a controlled bleaching eifect is desired. The solid peroxygen compound is employed in amounts suflicient to achieve the desired degree of bleaching. For home bleaching applications amounts suflicient to supply from about 10 to about 100 p.p.m. of active oxygen in the wash solution normally are employed. The preferred amount is that which will yield about 40 p.p.m. of active oxygen.

In the make-up of the final bleaching mixture it is desirable to keep the solid peroxygen compound and the activator out of contact with one another until placed in the avoid any possible reaction between these ingredients, even in the dry state. This can be done most readily when making up a single mixture by coating the activator with a water soluble, or dispersable coating prior to mixing it with the remaining components of the bleaching mix. In this way the activator and the solid peroxygen 3 compound can be mixed together and still remain out of contact with one another until the mixture is placed in the wash water. Another alternative is to separately package the solid peroxygen compound and the activator so that they are physically out of contact with one another in the consumer package.

The solid peroxygen compounds which are useful in the present process as bleaching, disinfecting and sanitizing agents are those which liberate perhydroxyl anions readily when dissolved in an aqueous media. These include the alkali perborates such as sodium perborate and other alkali metal percompounds such as percarbonates, persilicates, perphosphates, and perpyrophosphates. In addition, such compounds as sodium peroxide, zinc peroxide, calcium peroxide, magnesium peroxide, urea peroxide, and others are included within the term solid peroxygen compound.

In the practice of the present invention with peroxygen compounds such as hydrogen peroxide, the article to be treated is contacted with an aqueous solution containing the peroxygen compound, e.g. H and the present activator at ambient temperatures or above as desired. This is effective in bleaching wood pulp, commercial textiles, fats, oils and all common materials and compounds that are traditionally bleached with solutions of hydrogen peroxide. These aqueous solutions of the peroxygen compounds and the activator can also be used in sanitizing and disinfecting applications as well as for bleaching. The amount of peroxide utilized will vary with the specific material being treated. For example, the bleaching of fats or oils may require greater concentrations of peroxide than textile bleaching to achieve the desired whiteness. The present anyhydride activator is added, preferably in amounts sufficient to supply one mole of anhydride for every atom of available active oxygen, regardless of the quantity of peroxygen compound utilized in the treating solution.

The present activators may be of two types. The first are the mixed carboxylic acid anhydrides having the formula:

in which R is an aliphatic group and R is an aromatic group. These mixed anhydrides are the chemical combination of two different types of precursor carboxylic acids, an aliphatic monocarboxylic acid having from 2 to about 19 carbon atoms and an aromatic carboxylic acid. The aromatic acid, unlike the aliphatic carboxylic acid, can be a polycarboxylic acid having carboxylic groups other than that which is combined with the aliphatic carboxylic acid in the formation of the anhydride. However, any two carboxylic acid groups must not be attached to adjacent carbon atoms in the aromatic ring. For example, aromatic dibasic acid precursors such as isophthalic or terephthalic acid are acceptable, whereas phthalic acid, whose carboxyl groups are on adjacent carbon atoms in the aromatic ring, does not produce an acceptable mixed anhydride activator.

The second type of activator is a physical mixture of an aliphatic monocarboxylic acid anhydride (derived from an acyclic alipthatic monocarboxylic acid having from 2 to about 19 carbon atoms) and an aromatic carboxylic acid anhydride derived from an aromatic carboxylic acid. The aromatic carboxylic acid can be a monoor polycarboxylic acid, provided that no two carboxylic acid groups are attached to adjacent carbon atoms of the aromatic ring.

When a physical mixture of anhydrides, as described above, is employed as the activator, it is preferred that they be in equal molar ratio in order to obtain the maximum synergistic effect in the activation of the peroxygen compound. Obviously, mixtures other than in a 1:1 molar ratio can be employed, but the desirable synergistic activation effect decreases as the proportion departs from this 1:1 molar ratio.

In practice when one utilizes a mixed carboxylic acid anhydride there are always present minor amounts of the corresponding carboxylic acid anhydrides from which it is formed. This is due to an equilibrium which results between the mixed carboxylic acid anhydride and its precursor acid anhydrides in accordance with the following equilibrium 2 o o o o o 2R g-O-( JR R (i0-i J-R R -i J0iiR where R is an aliptic group and R is an aromatic group.

In the make-up of the above anhydride activators, the aromatic or aliphatic groups of the anhydrides may be substituted with any functional substituents that are not oxidized by the peroxygen compound in solution. In the case of substituted aromatic groups, it is preferred that the aromatic substituent be electro negative such as halogens, i.e. chlorine or bromine, nitro groups, cyano groups, and the like.

Where additional carboxylic acid groups are present on the aromatic ring, these may further be combined with additional aliphatic carboxylic acids to form a multipleanhydride, e.g. diacetic anhydride of terephthalic acid. Alternately, these additional carboxylic acid groups can be combined with alkali metals to form alkali metal carboxylate groups. The aromatic group can have a limited number of electro positive groups such as alkyl groups, e.g. methyl groups, but these are not the preferred substituents on the aromatic ring because they tend to decrease the electro negativity of the aromatic moiety.

The aliphatic group of the anhydrides also may be substituted with functional substituents that are not oxidized by the peroxygen compound in solution. It is preferred that these groups be electro positive substituents such as aliphatic side chains, e.g. methyl or ethyl groups. However, a limited number of electro negative groups, such as chlorine or bromine, nitro groups, cyano groups, and the like can be present. These electro negative groups are not the preferred substituents because they decrease the electro positive nature of the aliphatic group of the anhydride.

The present mixed carboxylic acid anhydrides can be produced by a variety of processes. These include the reaction of an aliphatic anhydride such as acetic anhydride with an aromatic carboxylic acid, eg benzoic acid, at temperatures of from about ambient to about 70 C. The result of the above reaction is a mixed carboxylic acid anhydride having both aromatic and aliphatic moieties. The reaction proceeds according to the following equation:

where R is an aliphatic group and R is an aromatic group.

A method for acetylating an aromatic carboxylic acid, e.g. benzoic acid, is by reacting ketene with the acid in an inert solvent. A mixed anhydride is formed, e.g. aceticbenzoic acid anhydride, as a product of the reaction as follows:

The preferred mixed anhydrides are those which are most easily prepared such as the benzoic-acetic anhydride, further these mixed anhydrides are more effective per unit weight than the substituted, more complex anhydrides.

The following examples are given to illustrate the present invention and are not deemed to be limiting thereof.

Example 1 Run A.Bleaching tests were carried out by bleaching tea, coffee and Wine stained cotton swatches (5" x 5") with sodium perborate tetrahydrate alone and in the presence of various activators. The procedure used was as follows: 32 cotton swatches (5" x 5" desized cotton Indianhead fabric, 48 fill by 48 warps threads per inch, uniform in weave and thread count) were stained with tea, cofiee and wine in the following manner. Five tea bags were placed in a liter of water and boiled for 5 minutes. Thereafter, the swatches were immersed in the tea and the boiling continued for 5 minutes. Thirty-two additional swatches of the same cloth were coffee stained by boiling 50 g. of coffee in a liter of water, immersing the swatches in the coifee solution, and boiling for an additional 5 minutes. The wine stains were created by soaking swatches of the same cloth in a red wine at room temperature. The stained-swatches Were then squeezed to remove excess fluid, dried, rinsed in cold water, and dried. Three of the stained cotton swatches were then added to each of a series of stainless steel Terg-o-Tometer vessels (produced by the US. Testing Company) containing 1000 ml. of a 0.2% standard detergent solution at a temperature of 120 F. Measured amounts of sodium perborate tetrahydrate bleach were then added to each vessel sufficient to correspond to an active oxygen content of 60 p.p.m. The pH of the solutions was adjusted to'9.0 using soda ash. Cutup pieces of white terry cloth toweling were then added to provide a typical household wash water: cloth ratio of 20:1. The activators specified in Table I were then added to the solution in the ratio set forth in Table I. The Tergo-Tometer was then operated at 72 cycles per minute for minutes at a temperature of 120 F. At the end of the wash cycle, the swatches were removed, rinsed under cold tap water and dried in a Proctor-Schwartz skein dryer. The tests were run in triplicate and included detergent blanks. Refiectance readings of the swatches were then taken before and after the wash cycle with a Hunter Model D-40 Reflectometer and the readings were averaged. The percent stain removal was obtained according to the following formula:

Percent stain removal= Reflectance after bleaching- Refiectance before bleachingX 10 Reflectance before staining-Reflectance stained The results are reported in Table 1 below.

Run B.The following bleaching tests were conducted with various anhydrides or anhydride mixtures other than those specified in the present invention. These anhydrides were used in a 1:1 mole ratio tosodium perborate tetrahydrate under the same conditions as specified in Run A. The results of the bleaching tests are given below.

TABLE II Percent Stain Removal Activator Tea Coffee Wine 59.3 68.0 80. 6 Benzoie anhydride 61. O 72.0 83.0 Phthalic anhydrid 42. 5 57.6 77. 9 Maleic anhydride. 44. 4 57. 5 78. 1 Succinie anhydride 46. 9 65. 7 63. 8 Mixture of phthalic and suceinie anhyd de (1:1 mole ratio) 40. 2 59. 3 65. 6 Mixture of phthalic and maleic anhydride (1:1 mole ratio) 38. 0 66. 3 72. 6 Mixture of succinic and. maleic anhydride (1:1 mole ratio) 43. 2 69. 3 67. 0

As will be obvious from the results shown in Table II, the aliphatic dibasic anhydrides, such as maleic anhydride or succinic anhydride, are not good activators for the peroxygen bleaching compound. Similarly, mixtures of these aliphatic dibasic anhydrides do not show any substantial improvement over the use of these dibasic anhydrides separately. The monobasic anhydrides, such as benzoic anhydride or acetic anhydride when used alone, each show some activation of the peroxygen bleaching compound. However, the degee of bleaching improvement (percent stain removal) is very markedly lower than when a mixture of monobasic aliphatic and aromatic anhydrides is used as is illustrated in Table I. The use of a mixture of monobasic aliphatic and aromatic anhydrides appears to result in a synergistic activation of the peroxygen bleaching compound well beyond the mere additive eifect of these anhydrides when used separately.

Example 2 The procedure of Example 1 was repeated using only tea stained fabrics. Three dilferent fabrics were used in this test: cotton, a blend of 65% dacron and 35% cotton, and a blend of 65% acetate and 35% rayon fabric. The cotton was identical to that used in Example 1 and the other fabrics were likewise identical in thread count and weight, except for the contents of the fibers. The activator used was a mixture of acetic and benzoic anhydride in a mole ratio of 1:1. The activator was added to the Wash solution in amounts corresponding to 1:1 mole ratio of activator to sodium perborate tetrahydrate. The pH of the wash water was adjusted with soda ash to obtain the pH values listed in Table III. The results of the test are listed in Table III.

Example 3 The same bleaching test procedure was followed as described in Example 1, except that hydrogen peroxide was used instead of sodium perborate tetrahydrate and was added in amounts to obtain 60 p.p.m. active oxygen in the wash solution. The pH of the solution was adjusted to 9.0 using soda ash. The results are reported in Table IV.

TABLE IV Percent Stain Removal Tea Coffee Wine Activator Pursuant to the requirements of the patent statutes, the principle of this invention has been explained and exemplified in a manner so that it can be readily practiced by those skilled in the art, such exemplification including what is considered to represent the best embodiment of the invention. However, it should be clearly understood that, within the scope of the appended claims, the invention may be practiced by those skilled in the art, and having the benefit of this disclosure otherwise than as specifically described and exemplified herein.

What is claimed is:

1. A process for activating a peroxygen bleaching compound in an aqueous solution for use in bleaching textiles which comprises adding an activator to said aqueous solution consisting essentially of a mixed carboxylic acid anhydride having the formula:

where (1) R is an aliphatic group and II Rl C is derived from an aliphatic monocarboxylic acid having from 2 to about 19 carbon atoms, and

(2) R is an aromatic group and is derived from an aromatic carboxylic acid selected from the group consisting of aromatic mon'ocarboxylic acids and aromatic polycarb'oxylic acids in which said polycarboxy'lic acids have none of their carboxylic acid substituents attached to adjoining carbon atoms of the aromatic ring, said activator being added in amounts of about 1 mole per atom of available oxygen and being soluble in said aqueous bleaching solution in amounts of at least about 100 ppm.

2. Process of claim 1 in which the peroxygen bleaching compound is a solid peroxygen compound.

3. Process of claim 1 in Which the bleaching compound is hydrogen peroxide.

4. Process of claim 1 in which the peroxygen bleaching compound is an alkali perborate.

5. Process of claim 1 in which the activator is a mixed acetic-benzoic carboxylic acid anhydride.

6. Process of claim 1 in which the activator is the diacetic anhydride of isophthalic acid.

7. A process for activating a peroxygen compound in an aqueous solution which comprises adding an activator to said solution consisting essentially of a mixed carboxylic acid anhydride having the formula:

0 O R Jo("J-R where (l) R is an aliphatic group and is derived from an aliphatic monocarboxylic acid having from 2 to about 19 carbon atoms, and (2) R is an aromatic group and 0 ll C R2 is derived from an aromatic carboxylic acid selected from the group consisting of aromatic monocarboxylic acids and aromatic polycarboxylic acids in which said polycarboxylic acids have none of their carboxylic acid substituents attached to adjoining carbon atoms of the aromatic ring, said activator being added in amounts of about 1 mole per atom of available oxygen and being soluble in said aqueous treating solution in amounts of at least about ppm.

8. Process of claim 7 in which the peroxygen compound is a solid peroxygen compound.

9. Process of claim 7 in which the peroxygen compound is hydrogen peroxide.

10. Process of claim 7 in which the peroxygen compound is an alkali perborate.

11. Process of claim 7 in which the activator is a mixed acetic-benzoic carboxylic anhydride.

12. Process of claim 7 in which the activator is the diacetic anhydride of isophthalic acid.

References Cited UNITED STATES PATENTS 2,362,401 11/1944 Reichert et al 252-99 3,130,165 4/1964 Brocklehurst 252-186 X 3,163,606 12/1964 Vivein 252-99 FOREIGN PATENTS 1,038,693 9/1958 Germany.

LEON D. ROSDOL, Primary Examiner. M. WEINBLATT, Assistant Examiner. 

1. A PROCESS FOR ACTIVATING A PEROZYGEN BLEACHING COMPOUND IN AN AQUEOUS SOLUTION FOR USE IN BLEACHING TEXTILES WHICH COMPRISES ADDING AN ACTIVATOR TO SAID AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF A MIXED CARBOXYLIC ACID ANHYDRIDE HAVING THE FORMULA: 